Syntheses, structures and properties of three nonmetal borates with salicylic acid and organic amines

Three new borates containing nonmetal compounds, [C4H12N][BO4(C7H4O)2] (1), [C8H20N][BO4(C7H4O)2] (2) and [C6H18N2]0.5[BO4(C7H4O)2] (3) have been prepared, aiming at the formation of extended supramolecular networks with organic–inorganic hybrid materials of salicylic acid and boric acid. The corresponding compounds have been characterized by chemical and spectroscopic techniques. X-ray diffraction analyses of available single crystals revealed that the molecular structures of the three compounds have the same isolated [BO4(C7H4O)2]− anion. The [BO4(C7H4O)2]− anion with a distorted BO4 tetrahedron is formed by bidentate coordination of the B atom to two salicylic acid molecules via the O atoms of the central carboxyl and α-hydroxyl groups. The three compounds display violet luminescence with emission maxima around 365 nm.